To use terra-i offline (for example in the field) in an Android smartphone or tablet follow the instructions below.
Download the maps (-) Android app from https://play.google.com/store/apps/details?id=coderminus.maps
Download the terra-i configuration file from here from your Android browser and save as terra-i_offline.txt to /sdcard/coderminus.maps
Open the maps (-) app and navigate to settings>more>preferences>configure maps
Choose load from file and navigate up (..) and down to /sdcard/coderminus.maps to locate the file terra-i_offline.txt
Click save to save this configuration as a layer
Go back to the main map page and choose settings>select map and choose terra-i from the list
You can cache an area of the map by choosing settings>cache area or navigating to the zones places that you will visit in the field and the zoom levels that you need
You can upload GPX files of routes and/or activate the GPS under settings>more>preferences
Whilst in the field you can flick between the Google Map and the Terra-i map to use the terra-i data whilst offline